1. Technical Field
The present disclosure relates to enteral nutritional compositions comprising a prebiotic component. More specifically, the nutritional compositions of the present disclosure contain a prebiotic component comprising galactooligosaccharide (GOS). In some embodiments, the prebiotic component comprises galactooligosaccharide, polydextrose (PDX), a mixture of galactooligosaccharide and polydextrose, or a mixture of galactooligosaccharide, polydextrose and at least one other prebiotic. Moreover, the disclosure is further directed to a method of inhibiting adhesion of pathogens in the gastrointestinal tract of a human subject. The method comprises administering an effective amount of the prebiotic component.
2. Background Art
Infants and children are exposed to a variety of pathogens, and consequently, the incidence of infectious diseases peaks in the first 4 years of life. Infants do not have mature immune systems and are often incapable of mounting an effective immune response. Indeed, on a cellular level, infants have a decreased ability to concentrate leukocytes where necessary. (Maternity and Gynecologic Care, Bobak, Jensen, Zalar, Fourth Edition, p. 470) Consequently, infants are not able to limit invading pathogens due to a generalized hypofunction of their inflammatory and immune mechanisms. As such, improving the immune response in infants and children would provide an opportunity to reduce the incidence of infections and to maintain or improve the overall health of pediatric subjects.
Cronobacter sakazakii (also called Enterobacter sakazakii) is a motile, petrichious, non-sporeforming, Gram negative facultative anaerobe. It is an opportunistic pathogen that has been implicated in severe forms of meningitis, necrotizing enterocolitis, and sepsis in neonates. Although the environmental source of the microorganism is not known, powdered infant formula has been implicated in several outbreaks as well as other sporadic cases of infection. Of particular concern are reports of the organism being isolated from powdered milk processing plants and hospital utensils such as spoons and other implements used to prepare infant formula. (Mullane, N. R., D. Drudy, P. Whyte, M. O'Mahony, A. G. M. Scanell, P. G. Wall, S. Fanning. 2006. Enterobacter sakazakii: biological properties and significance in dried infant milk formula (IMF) powder. International Journal of Dairy Technology 59: 102-111.) Because colonization and subsequent infection, and invasion of C. sakazakii require that the organism adhere to host cell surfaces, agents that inhibit or block attachment of the pathogen to epithelial cells could be useful in reducing infections.
The infant gut microflora is rapidly established in the first few weeks following birth, and it has a great impact on an infant's immune system. The nature of this intestinal colonization is initially determined by the host's early exposure to environmental sources of microbes as well as to the health of the infant. Whether the infant is breast-fed or formula-fed also has a strong influence on the intestinal bacterial population.
Human milk contains a number of factors that may contribute to the growth and population of the gut microflora of infants. Among these factors is a complex mixture of more than 130 different oligosaccharides that reach levels as high as 8-12 g/L in transitional and mature milk. (Kunz, et al., Oligosaccharides in Human Milk: Structure, Functional, and Metabolic Aspects, Ann. Rev. Nutr. 20: 699-722 (2000).) These oligosaccharides are resistant to enzymatic digestion in the upper gastrointestinal tract, and they reach the colon intact, where they then serve as substrates for colonic fermentation.
Human milk oligosaccharides are believed to elicit an increase in the number of Bifidobacteria in the colonic microflora, along with a reduction in the number of potentially pathogenic bacteria. (Kunz, et al., Oligosaccharides in Human Milk: Structure, Functional, and Metabolic Aspects, Ann. Rev. Nutr. 20: 699-722 (2000); Newburg, Do the Binding Properties of Oligosaccharides in Milk Protect Human Infants from Gastrointestinal Bacteria?, J. Nutr. 217:S980-5984 (1997).) One way that human milk oligosaccharides may increase the numbers of Bifidobacterium spp. and reduce the number of potentially pathogenic bacteria is by acting as competitive receptors and inhibiting the binding of pathogens to the cell surface. Rivero-Urgell, et al., Oligosaccharides: Application in Infant Food, Early Hum. Dev. 65(S):43-52 (2001).
Because cow's milk and many commercially available infant formulas that are based on cow's milk provide only trace amounts of oligosaccharides, prebiotics can be used to supplement the diet of formula-fed infants. Prebiotics have been defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of cells in the colon that can improve the health of the host.
The incorporation of various prebiotic ingredients into infant formulas has been disclosed. For example, U.S. Patent App. No. 20030072865 to Bindels, et al. discloses an infant formula with improved protein content and at least one prebiotic. The prebiotic component can be lacto-N-tetaose, lacto-N-fuco-pentaose, lactulose (LOS), lactosucrose, raffinose, galactooligosaccharide, fructo-oligosaccharide (FOS), oligosaccharides derived from soybean polysaccharides, mannose-based oligosaccharides, arabino-oligosaccharides, xylo-oligosaccharides, isomalto-oligo-saccharides, glucans, sialyl oligosaccharides, and fuco-oligosaccharides.
Similarly, U.S. Patent App. No. 2004/0191234 to Haschke discloses a method for enhancing the immune response which comprises administering at least one prebiotic. The prebiotic can be an oligosaccharide produced from glucose, galactose, xylose, maltose, sucrose, lactose, starch, xylan, hemicellulose, inulin, or a mixture thereof. The prebiotic can be present in an infant cereal.
Unfortunately, however, there are some disadvantages in the administration of the above to formula-fed infants. While they may beneficially affect the population of probiotics in the gut, the fermentation of many of these prebiotic substances occurs at a very rapid rate, which may produce excess gas, abdominal distension, bloating, and diarrhea. Therefore, the choice of prebiotic substances in nutritional compositions and infant formulas should be made with the goal of maximizing potential benefits, such as inhibiting the adhesion of pathogens, and minimizing unwanted side-effects.